Systems and methods for generating stabilized images of a real environment in artificial reality

ABSTRACT

A method includes a computing system tracking motions performed by a hand of a user, determining one or more anchor locations in a three-dimensional space, and generating a virtual surface anchored in the three-dimensional space. An image of a real environment is captured using a camera worn by the user, and a pose of the camera when the image is captured is determined. The computing system determines a first viewpoint of a first eye of the user and a region in the image that, as viewed from the camera, corresponds to the virtual surface. The computing system renders an output image based on (1) the first viewpoint relative to the virtual surface and (2) the image region corresponding to the virtual surface, and displays the output image on a first display of the device, the first display being configured to be viewed by the first eye of the user.

TECHNICAL FIELD

This disclosure generally relates to computer graphics and 3Dreconstruction techniques.

BACKGROUND

Artificial reality is a form of reality that has been adjusted in somemanner before presentation to a user, which may include, e.g., a virtualreality (VR), an augmented reality (AR), a mixed reality (MR), a hybridreality, or some combination and/or derivatives thereof. Artificialreality content may include completely generated content or generatedcontent combined with captured content (e.g., real-world photographs).The artificial reality content may include video, audio, hapticfeedback, or some combination thereof, and any of which may be presentedin a single channel or in multiple channels (such as stereo video thatproduces a three-dimensional effect to the viewer). Artificial realitymay be associated with applications, products, accessories, services, orsome combination thereof, that are, e.g., used to create content in anartificial reality and/or used in (e.g., perform activities in) anartificial reality. The artificial reality system that provides theartificial reality content may be implemented on various platforms,including a head-mounted display (HMD 104) connected to a host computersystem, a standalone HMD 104, a mobile device or computing system, orany other hardware platform capable of providing artificial realitycontent to one or more viewers.

SUMMARY OF PARTICULAR EMBODIMENTS

“Passthrough” is a feature that allows a user to see his physicalenvironment while wearing an artificial reality device. Informationabout the user's physical environment is visually “passed through” tothe user by having the device display information captured by theheadset's external-facing cameras. The present invention improves thestability and resource requirements associated with rendering anddisplaying passthrough images by defining a particular region or virtualsurface of the virtual environment, for example a plane or planarsurface, for displaying passthrough images (a “passthrough area”). Whenthe virtual surface corresponds to, for example, a particular physicalsurface in the real environment that the user frequently interacts with(e.g., the user's desk, a tabletop, the user's hands, or a canvas on awall), there is no need to continuously calculate the depth of thepassthrough area as the user moves throughout a three-dimensionalenvironment, because the particular physical surface in the realenvironment remains at a fixed pose.

In particular embodiments the computing system requests the user toperform a one-time setup to specify anchor locations and determine apose of the virtual surface in the real environment, through forexample, one or more controller or hand movements. Once defined, thecomputing system may receive images and identify one or more regions ofthe image that correspond to the virtual surface. The computing systemmay display the passthrough images on a device display associated with auser based on one or more criteria, for example the distance between theuser and the virtual surface. Additionally, the computing system mayalso display passthrough images for the surrounding walls, floor, etc.that are nearby or adjacent to the virtual surface. In particularembodiments, the computing system may apply one or more visual effectsto enhance the display of the one or more passthrough images to theuser.

The embodiments disclosed herein are only examples, and the scope ofthis disclosure is not limited to them. Particular embodiments mayinclude all, some, or none of the components, elements, features,functions, operations, or steps of the embodiments disclosed herein.Embodiments according to the invention are in particular disclosed inthe attached claims directed to a method, a storage medium, a system anda computer program product, wherein any feature mentioned in one claimcategory, e.g. method, can be claimed in another claim category, e.g.system, as well. The dependencies or references back in the attachedclaims are chosen for formal reasons only. However any subject matterresulting from a deliberate reference back to any previous claims (inparticular multiple dependencies) can be claimed as well, so that anycombination of claims and the features thereof are disclosed and can beclaimed regardless of the dependencies chosen in the attached claims.The subject-matter which can be claimed comprises not only thecombinations of features as set out in the attached claims but also anyother combination of features in the claims, wherein each featurementioned in the claims can be combined with any other feature orcombination of other features in the claims. Furthermore, any of theembodiments and features described or depicted herein can be claimed ina separate claim and/or in any combination with any embodiment orfeature described or depicted herein or with any of the features of theattached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an example artificial reality system worn by a user,in accordance with particular embodiments.

FIG. 1B illustrates an example of a passthrough feature, in accordancewith particular embodiments.

FIGS. 2A and 2B illustrate top-down visualizations of a 3D mesh beingdeformed to represent the contours of an observed environment.

FIG. 3 provides an illustration of 3D-passthrough rendering based on the3D mesh.

FIG. 4 illustrates one or more cameras associated with the artificialreality device of a user capturing the physical environment of the user.

FIG. 5 illustrates a first-person perspective of a user defining avirtual surface for displaying passthrough images in a three-dimensionalenvironment.

FIG. 6A illustrates rendering one or more output passthrough images onthe virtual surface.

FIG. 6B illustrates rendering one or more passthrough images on thevirtual surface from the perspective of a user's eyes.

FIG. 7 illustrates one or more passthrough images displayed on a devicedisplay associated with a user.

FIGS. 8A-8C illustrate selectively displaying passthrough images basedon a location or orientation of an artificial reality device.

FIG. 9 illustrates an example method for displaying stabilized images ofa real environment in artificial reality.

FIG. 10 illustrates an example network environment associated with asocial-networking system.

FIG. 11 illustrates an example computer system.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1A illustrates an example of an artificial reality system 100 wornby a user 102. In particular embodiments, the artificial reality system100 may comprise a head-mounted device (“HMD 104”) 104, a controller106, and a computing system 108. The HMD 104 may be worn over the user'seyes and provide visual content to the user 102 through internaldisplays (not shown). The HMD 104 may have two separate internaldisplays, one for each eye of the user 102. As illustrated in FIG. 1A,the HMD 104 may completely cover the user's field of view. By being theexclusive provider of visual information to the user 102, the HMD 104achieves the goal of providing an immersive artificial-realityexperience. One consequence of this, however, is that the user 102 wouldnot be able to see the physical (or real) environment surrounding him,as his vision is shielded by the HMD 104. As such, the passthroughfeature described herein is needed to provide the user with real-timevisual information about his physical environments.

Referring again to FIG. 1A, the HMD 104 may have external-facingcameras, such as the two forward-facing cameras 105A and 105B shown inFIG. 1A. While only two forward-facing cameras 105A-B are shown, the HMD104 may have any number of cameras facing any direction (e.g., anupward-facing camera to capture the ceiling or room lighting, adownward-facing camera to capture a portion of the user's face and/orbody, a backward-facing camera to capture a portion of what's behind theuser, and/or an internal camera for capturing the user's eye gaze foreye-tracking purposes). The external-facing cameras 105A and 105B areconfigured to capture the physical environment around the user and maydo so continuously to generate a sequence of frames (e.g., as a video).

In particular embodiments, the pose (e.g., position and orientation) ofthe HMD 104 within the environment may be needed. For example, in orderto render an appropriate display for the user 102 while he is movingabout in a virtual environment, the system 100 would need to determinehis position and orientation at any moment. Based on the pose of the HMD104, the system 100 may further determine the viewpoint of either of thecameras 105A and 105B or either of the user's eyes. In particularembodiments, the HMD 104 may be equipped with inertial-measurement units(“IMU”). The data generated by the IMU, along with the stereo imagerycaptured by the external-facing cameras 105A-B, allow the system 100 tocompute the pose of the HMD 104 using, for example, SLAM (simultaneouslocalization and mapping) or other suitable techniques.

In particular embodiments, the artificial reality system 100 may furtherhave one or more controllers 106 that enable the user 102 to provideinputs. The controller 106 may communicate with the HMD 104 or aseparate computing unit 108 via a wireless or wired connection. Thecontroller 106 may have any number of buttons or other mechanical inputmechanisms. In addition, the controller 106 may have an IMU so that theposition of the controller 106 may be tracked. The controller 106 mayfurther be tracked based on predetermined patterns on the controller.For example, the controller 106 may have several infrared LEDs or otherknown observable features that collectively form a predeterminedpattern. Using a sensor or camera, the system 100 may be able to capturean image of the predetermined pattern on the controller. Based on theobserved orientation of those patterns, the system may compute thecontroller's position and orientation relative to the sensor or camera.

The artificial reality system 100 may further include a computer unit108. The computer unit may be a stand-alone unit that is physicallyseparate from the HMD 104 or it may be integrated with the HMD 104. Inembodiments where the computer 108 is a separate unit, it may becommunicatively coupled to the HMD 104 via a wireless or wired link. Thecomputer 108 may be a high-performance device, such as a desktop orlaptop, or a resource-limited device, such as a mobile phone. Ahigh-performance device may have a dedicated GPU and a high-capacity orconstant power source. A resource-limited device, on the other hand, maynot have a GPU and may have limited battery capacity. As such, thealgorithms that could be practically used by an artificial realitysystem 100 depends on the capabilities of its computer unit 108.

“Passthrough” is a feature that allows a user to see his physicalenvironment while wearing HMD 104. Information about the user's physicalenvironment is visually “passed through” to the user by having the HMD104 display information captured by the headset's external-facingcameras 105A and 105B. FIG. 1B illustrates an example of the passthroughfeature. A user 102 may be wearing an HMD 104, immersed within athree-dimensional space, for example and not by way of limitation, avirtual reality environment. A physical table 150 is in the physicalenvironment surrounding the user 102. However, due to the HMD 104blocking the vision of the user 102, the user 102 is unable to directlysee the table 150. To help the user perceive his physical environmentwhile wearing the HMD 104, the passthrough feature captures informationabout the physical environment using, for example, the aforementionedexternal-facing cameras 105A-B. Methods for rendering and displayingpassthrough images are described further in U.S. application Ser. No.16/746,128, filed Jul. 24, 2020, entitled “Systems, Methods, and Mediafor Generating Visualization of Physical Environment in ArtificialReality,” hereby incorporated by reference in its entirety.

Simply displaying the captured images would not work as intended,however. Since the locations of the cameras 105A-B do not coincide withthe locations of the user's eyes, simply displaying the captured imageswould not provide the user 102 with an accurate view of the physicalenvironment since the cameras 105A-B cannot physically be located at theexact same viewpoint as the user's eyes. As such, the passthroughfeature described herein uses a re-projection technique that generates a3D representation of the physical environment and then renders imagesbased on the 3D representation from the viewpoints of the user's eyes.The captured information may then be re-projected to the user 102 basedon his viewpoints. In particular embodiments where the HMD 104 has aright display 160A for the user's right eye and a left display 160B forthe user's left eye, the system 100 may individually render (1) are-projected view 150A of the physical environment for the right display160A based on a viewpoint of the user's right eye and (2) a re-projectedview 150B of the physical environment for the left display 160B based ona viewpoint of the user's left eye.

In particular embodiments, the 3D representation may be generated basedon depth measurements of physical objects observed by the cameras105A-B. Depth may be measured in a variety of ways. In particularembodiments, depth may be computed based on stereo images. For example,the two forward-facing cameras 105A-B may share an overlapping field ofview and be configured to capture images simultaneously. As a result,the same physical object may be captured by both cameras 105A-B at thesame time. For example, a particular feature of an object may appear atone pixel pA in the image captured by camera 105A, and the same featuremay appear at another pixel pB in the image captured by camera 105B. Aslong as the depth measurement system knows that the two pixelscorrespond to the same feature, it could use triangulation techniques tocompute the depth of the observed feature. For example, based on thecamera 105A's position within a 3D space and the pixel location of pixelpA relative to the camera 105A's field of view, a line could beprojected from the camera 105A and through the pixel pA. A similar linecould be projected from the other camera 105B and through the pixel pB.Since both pixels are supposed to correspond to the same physicalfeature, the two lines should intersect. The two intersecting lines andan imaginary line drawn between the two cameras 105A and 105B form atriangle, which could be used to compute the distance of the observedfeature from either camera 105A or 105B or a point in space where theobserved feature is located.

In addition, since the images have no depth, simply displaying theimages would not provide the user with proper parallax effects if hewere to shift away from where the images were taken. Incorrect parallax,coupled with user motion, could lead to motion sickness. Thus, togenerate correct parallax, particular embodiments of the passthroughfeature extracts information about the environment from the capturedimages (e.g., depth information), use the information to generate a 3Dmodel (a geometric scene representation) of the physical environment,and reconstruct a scene of the modeled environment from the user'scurrent viewpoint.

Photon-to-visuals latency is another issue addressed by the passthroughfeature. The delay between a photon hitting the camera and it appearingon the screen (as part of the captured image) determines the visualcomfort of interacting in a dynamic world. Particular embodiments of thepassthrough feature overcomes this issue by updating the 3D modelrepresentation of the environment based on images captured at asufficiently high rate (e.g., at 30 Hz, 60 Hz, etc.) and renderingimages based on the latest known head pose of the user.

The passthrough image can be unstable (e.g., it warps visibly) andresource-intensive to render and display because the 3D representationmust be continuously updated as the user moves throughout the physicalenvironment. Further, the depth estimations of objects are ofteninaccurate. Over time, this leads to inaccuracies and inconsistencies inthe 3D representation from the viewpoints of the user's eyes, especiallywith regard to the estimated depth of one or more objects in thephysical environment. Thus, while usable for basic functions, thesepassthrough techniques make it difficult for a user to perform tasks orinteract with objects in the physical environment (e.g., typing on areal keyboard, picking up a mobile phone from a table) while in thevirtual environment. Further, the inaccuracies in the 3D representationmay result in an aesthetically inconsistent experience due to warping ofthe displayed images.

FIGS. 2A and 2B illustrate top-down visualizations of a 3D mesh beingdeformed to represent the contours of an observed environment. Forclarity, the figures are drawn in 2D, but it should be understood thatthe 3D mesh is a 3D construct. FIG. 2A illustrates an embodiment of the3D mesh 200A being initialized to be equal-distance (e.g., 1, 2, 2.5, or3 meters) from a viewer 210 (represented by a camera). In the particularexample being shown, the radius of the 3D mesh 200A is 2 meters. Sincethe 3D mesh 200A is equal-distance away from the viewer 210, it forms ahemisphere around the user. For clarity, FIG. 2A illustrates a portionof a cross-section of that hemisphere, resulting in the half-circleshown. FIG. 2A further illustrates points (e.g., 220) in the point cloudthat are deemed reliable. These points 220 represent observed featuresin the environment and may be generated using the embodiments describedelsewhere herein.

The 3D mesh 200A may be deformed according to the points 220 in order tomodel the contour of the environment. In particular embodiments, the 3Dmesh 200A may be deformed based on the viewer's 210 position and thepoints 220 in the point cloud. To determine which portion of the 3D mesh200A corresponds to each point in the point cloud 220, the computingdevice may cast a conceptual ray from the viewer's 210 position towardsthat point. Each ray would intersect with a primitive (e.g., a triangleor other polygon) of the 3D mesh. For example, FIG. 2A shows a ray 230being cast from the viewer 210 towards point 220A. The ray 230intersects the 3D mesh 200A at a particular location 240. As a result,mesh location 240 is deformed based on the depth value associated withthe point 220A. For example, if the point 220 is 2.2 meters away fromthe viewer 210, the depth value associated with the mesh location 240may be updated to become 2.2 meters from its initial value of 2 meters.FIG. 2B illustrates the deformed 3D mesh 200B that may result from thedeformation process. At this point, the deformed mesh 200B representsthe contour of the physical environment observed by the viewer 210.

FIG. 3 provides an illustration of 3D-passthrough rendering based on the3D mesh. In particular embodiments, the rendering system may determinethe user's 102 current viewing position relative to the environment. Inparticular embodiments, the system may compute the pose of the HMD 104using SLAM or other suitable techniques. Based on the known mechanicalstructure of the HMD 104, the system could then estimate the viewpointsof the user's eyes 300A and 300B using offsets from the pose of the HMD104. In particular embodiments the computing system may determine aviewpoint that corresponds to a first eye of the user (e.g., a firstviewpoint that corresponds to a right eye of the user). In particularembodiments the computing system may determine a viewpoint thatcorresponds to a second eye of the user (e.g., a second viewpoint thatcorresponds to a left eye of the user). One or more viewpoints may bedetermined by utilizing any of the sensor data or image data received bythe computing system. A viewpoint of a particular eye may comprise alocation, an orientation, and a field of view from the particular eye.In particular embodiments the location and orientation comprising theviewpoint may be represented using one or more coordinate systems, forexample and not by way of limitation, via an absolute global coordinatesystem (e.g., x, y, z), or via a localized coordinate system relative toone or more components of artificial reality system, for example and notby way of limitation, the HMD 104.

The system may then render a passthrough image for each of the user'seyes 300A-B. For example, to render a passthrough image for the user'sright eye 300A, the system may cast a ray 320 from the estimatedviewpoint of the right eye 300A through each pixel of a virtual screenspace 310A to see which portion of the mesh 300B the rays wouldintersect. This ray casting process may be referred to as a visibilitytest, as the objective is to determine what is visible from the selectedviewpoint 300A. In the particular example shown, the ray 320 projectedthrough a particular pixel 322 intersects with a particular point 321 onthe mesh. This indicates that the point of intersection 321 is to bedisplayed by the pixel 322. Once the point of intersection 321 is found,the rendering system may sample a corresponding point in a texture imagethat is mapped to the point of intersection 321. In particularembodiments, the image captured by the cameras 105A-B of the HMD 104 maybe used to generate a texture for the mesh 300B. Doing so allows therendered image to appear more like the actual physical object. In asimilar manner, the rendering system may render a passthrough image forthe user's left eye 300B. In the example shown, a ray 330 may be castfrom the left-eye viewpoint 300B through pixel 332 of the left screenspace 310B. The ray 330 intersects the mesh 300B at location 331. Therendering system may then sample a texture image at a texture locationcorresponding to the location 331 on the mesh 300B and compute theappropriate color to be displayed by pixel 332. Since the passthroughimages are re-rendered from the user's viewpoints 300A-B, the imageswould appear natural and provide proper parallax effect.

The present invention remedies the stability and resource requirementsassociated with updating the 3D mesh by defining a particular region orvirtual surface, for example a plane or planar surface (hereinafter“virtual surface”) in the virtual environment for displaying passthroughimages (a “passthrough area”). When the virtual surface corresponds to,for example, a particular physical surface in the real environment thatthe user frequently interacts with (e.g., the user's desk, a tabletop,the user's hands, or a canvas on a wall), the computer system does notneed to continuously calculate the depth of the passthrough area as theuser moves throughout a three-dimensional environment, because theparticular physical surface in the real environment remains at a fixedpose (e.g., location and orientation). Thus, in one embodiment thevirtual surface may be located at a fixed pose (e.g., location andorientation) in the virtual environment that corresponds to or isassociated with the pose of the particular physical surface. In thismanner the pose of the virtual surface may be anchored with respect tothe physical environment (e.g., the virtual surface is fixed to aphysical tabletop). In particular embodiments the computing systemrequests the user to perform a one-time setup to specify anchorlocations and determine a pose of the virtual surface (e.g., the usercould designate a coordinate or the dimensions of the desk in the realenvironment using a controller).

In particular embodiments the surface geometry of the virtual surfacemay static and remain temporally fixed in the virtual environment, suchthat the user-defined virtual surface simply coincides with the locationof a physical surface. Because the surface geometry is definedindependently from the actual depth measurements on the correspondingphysical surface (in contrast to the methods described in FIGS. 2 and3), the virtual surface remains the same regardless of changes to thephysical surface. For example, if the user relocates one or more objectslocated on the particular physical object or surface that corresponds tothe virtual surface (e.g., the user picks up their phone off thetabletop), the surface geometry may remain constant. The computingsystem projects the passthrough images of random objects on the physicalsurface onto the virtual surface, regardless of the physical depth ofthe random objects.

By defining and fixing these parameters, the computing system cangenerate a corresponding virtual surface that is fixed in the virtualenvironment and provide temporally stable passthrough images for theuser. With the virtual surface anchored within the virtual environment,the computing system can render and display passthrough images withouthaving to continuously track and update the depth of the virtual surfaceas the user moves throughout the physical environment. Further, becausethe defined surface is virtual, the real surface can contain any numberof real objects (which can also be moved on the surface) without theusual difficulty of updating and reconstructing a 3D representation or3D mesh of the passthrough area and accompanying objects. Thissignificantly improves the passthrough experience.

In particular embodiments the computing system may capture one or moreimages of the real environment (also referred to as the physicalenvironment) and physical surroundings using a camera worn by the user.For example, the computing system may have a camera capture one or moreimages from a particular current perspective of the user. In particularembodiments the camera worn by the user is associated with an artificialreality device, for example a head-mounted device worn by the user thatblocks the user from seeing the real environment directly. In oneembodiment for generating passthrough images, a computing system mayaccess one or more images of an environment captured by cameras 105A and105B of a device worn by a user. The one or more images may include, forexample, a particular physical surface that the user frequentlyinteracts with (e.g., the user's desk, a tabletop, the user's hands, ora canvas on a wall) that was utilized to determine the virtual surface.The system may generate in some embodiments, based on the one or moreimages, depth measurements of one or more objects in the environment. Insome embodiments, the system may generate a mesh covering a field ofview of the user and then update the mesh based on the depthmeasurements to represent a contour of the objects in the environment.

In particular embodiments the computing system may determine a pose ofeach of the one or more cameras 105A and 105B when the image wascaptured. The camera pose may be determined by utilizing any of thesensor data or image data received by the computing system, for example,image or sensor data received by the HMD 104 of the user. In particularembodiments the camera pose may be determined based on a known spatialrelationship between the pose of the one or more cameras and the pose ofone or more components of the artificial reality system, for example theHMD 104. Based on, for example, the pose of the HMD 104, the computingsystem may further determine the pose of either of the cameras 105A and105B or either a pose of one or more of the user's eyes. The camera posemay comprise a location and an orientation of the camera. In particularembodiments the location and orientation comprising the camera pose maybe represented using one or more coordinate systems, for example and notby way of limitation, via an absolute global coordinate system (e.g., x,y, z), or via a localized coordinate system relative to one or morecomponents of artificial reality system, for example and not by way oflimitation, the HMD 104 or the one or more controllers 106.

FIG. 4 illustrates one or more cameras associated with the artificialreality device of a user capturing the physical environment of the user.The physical environment 400 may contain one or more physical surfaces405 that could be utilized to define a virtual surface according to themethods described herein, for example a tabletop or a painting asdepicted in FIG. 4. The one or more physical surfaces 405 may furtherinclude one or more objects the user wishes to interact with, forexample a keyboard, cell phone, or documents as depicted in FIG. 4. Asthe user moves through the physical environment, the one or more cameras105A-B may capture one or more images of the physical environment. Thecomputing system may display these one or more images to assist the userin defining one or more anchor locations or virtual surfaces.

FIG. 5 illustrates a first-person perspective of a user defining avirtual surface for displaying passthrough images in a three-dimensionalenvironment. In particular embodiments the computing system maydetermine one or more poses or anchor locations in order to generate avirtual surface. For example, the computing system may display one ormore images 500 to the user of an artificial reality system, where theimages 500 represent the physical environment while the user is wearingHMD 104. By viewing their physical environment, the user or computingsystem can identify and determine one or more anchor locations 510(e.g., one or more coordinates, lines, or perimeters) to define avirtual surface 505 with which to render and display passthrough images.In particular embodiments, the anchor locations and correspondingvirtual surface 505 may correspond to a location or orientation of aparticular physical surface in the real environment. In particularembodiments, the virtual surface may be determined by a defineddimension, area, contour, or orientation (e.g., the user may define avirtual surface that is a rectangle with dimensions 2 feet by 3 feet).

In particular embodiments, the computing system may determine anddesignate the one or more coordinates of the virtual surface 505 basedon the computing system tracking one or more motions performed by theuser. As depicted in FIG. 5, the user defines the virtual surface 505 byusing one or more motions to define or trace one or more anchorlocations 510 (e.g., a perimeter of the virtual surface). These one ormore motions may be performed, for example and not by way of limitation,by hand motions or eye motions that are tracked by the computing system.The one or more motions may be further associated with an interactionwith one or more controllers 106, for example, movements with thecontrollers or input received through one or more buttons or mechanicalinput mechanisms. The motions for designating one or more anchorlocations 510 may comprise, for example and not by way of limitation,placing a hand or controller at a particular coordinate or pointing ator selecting a particular coordinate in the three-dimensionalenvironment. The motions for determining one or more dimensions maycomprise, for example and not by way of limitation, using a hand orcontroller to trace a length width or height, or tracing a perimeter ofan area (e.g., tracing, click-and-drag, or drag-select motions). Inparticular embodiments the computing system may render and display oneor more icons, images, or representations overlaid over the passthroughimages 500 so the user can visualize the virtual surface 505 and one ormore anchor locations 510 as they are defined.

In particular embodiments the one or more anchor locations 510 ordimensions may be determined using computing vision techniques. Basedon, for example and not by way of limitation, an image captured from aviewpoint in the environment, a computer system may recognize objects(e.g., an art canvas, a desk, etc.) or portions of objects (e.g., thecorner of a table) in the image and compute depth information todetermine the locations of the one or more objects or portions ofobjects in the three-dimensional environment. With the accuratelocations of the objects in the three-dimensional environment, thesystem may perform a variety of functions, such as determining one ormore poses of objects (e.g., a location and orientation in thethree-dimensional space) or anchor locations 510 (e.g., one or morecoordinates, lines, or perimeters) within a three-dimensional space inorder to determine a virtual surface for rendering and displayingpassthrough images.

In particular embodiments the one or more anchor locations may representa location in the real environment that remains at a fixed (i.e.,“anchored”) position and orientation over time. One or more anchorlocations may comprise one or more coordinates, a dimension (e.g., alength), an area, or a volume. The one or more anchor locations may berepresented by one or more coordinate systems in the three-dimensionalspace, for example and not by way of limitation, via an absolute globalcoordinate system (e.g., x, y, z) or via a localized coordinate systemrelative to one or more objects in the three-dimensional space.

In particular embodiments the one or more anchor locations correspond toa location of one or more objects, regions, or surfaces in the realenvironment (e.g., one or more anchor locations may correspond to thecorner of a desk, a length of a wall, a masking canvas area, etc.). Forexample and not by way of limitation, the computing system may determinea coordinate that corresponds to the corner of a table, or an area ofthe surface of a desk. In particular embodiments the computing systemmay use the one or more coordinates or dimensions to determine the oneor more anchor locations for determining the virtual surface.

In particular embodiments the computing system may generate a virtualsurface 505 or volume in the three-dimensional space. This virtualsurface 505 may be generated based on the one or more of the anchorlocations determined according to the methods described herein. Inparticular embodiments the position, orientation, shape, contour, ordimensions of the virtual surface 505 may remain at a fixed (i.e.,“anchored”) position and orientation over time. These fixed propertiesmay correspond to one or more of the defined anchor locations, or one ormore objects in the physical environment (e.g., a virtual surface withdefined 3 feet by 2 feet rectangular dimensions may correspond to arectangular table top in the physical environment with the samedimensions). The generated virtual surface 505, which remains fixed inthe three-dimensional space by the computing system, allows for temporalstability when projecting the passthrough images, as the definedlocation and corresponding depth of the 3D surface relative to the userand HMD 104 need not be constantly estimated and updated.

In particular embodiments, the computing system may utilize the virtualsurface to render one or more output passthrough images for the virtualsurface. FIG. 6A illustrates rendering one or more output passthroughimages on the virtual surface. In particular embodiments the computingsystem may receive one or more images captured by the cameras 105A-B torender one or more passthrough images from the perspective of the camera610 on the virtual surface. The computing system may receive one or moreimages to determine one or more regions in the one or more images that,as viewed from the pose of the cameras 105A or 105B, corresponds to thevirtual surface when viewed from the perspective of the user of the HMD104. In particular embodiments this determination may be based on, forexample, the known spatial relationships between, for example, the poseof the one or more cameras on the HMD 104, the pose of the user 102 orthe HMD 104, or the pose of the one or more anchor locations or virtualsurface. For example, if the user turns their head such that the virtualsurface 505 is now on the peripheral of one or more images captured bythe cameras 105A or 105B, the computing system may use the pose of theHMD 104 or the one or more cameras 105A or 105B relative to the pose ofthe anchor locations or virtual surface 505 to ensure the passthroughimages remain properly projected onto the corresponding regions ofvirtual surface. This may require the computing system to determine acamera or HMD 104 pose associated with an image, and use the spatialproperties of this pose (e.g., the location, orientation, andfield-of-view) to determine a region of the image contains at least aportion of the virtual surface. As another example, in particularembodiments this determination of a region of the images that correspondto the virtual surface can be based on one or more computer visiontechniques (e.g., object recognition). In particular embodiments thecomputing system may further render one or more pixels to the virtualsurface 505 to map the geometry to the image information to, forexample, generate texture for the virtual surface.

However, in order to provide the correct perspective, the computingsystem must render the output passthrough images from the perspective ofthe user's eyes 500A-B. FIG. 6B illustrates rendering one or morepassthrough images on the virtual surface from the perspective of auser's eyes. If the computing system simply displayed the one or morerendered images 610 from the perspective of the cameras 500A-B, theprojected images would not provide the user 102 with an accurate view ofthe physical environment. Thus, the computing system may render one ormore passthrough images from the perspective of the user's eyes 615. Inparticular embodiments the computing system may render a first outputpassthrough image from the perspective of the user's eyes based on (1) afirst viewpoint or perspective from a first eye of the user relative tothe virtual surface and (2) the image region corresponding to thevirtual surface. In particular embodiments the computing system mayrender a second output image based on (1) a second viewpoint orperspective from a second eye relative to the virtual surface and (2)the image region corresponding to the virtual surface. When the systemrenders a one or more output passthrough images from the perspective ofthe user's eyes 615 for display, the system may perform visibility testsfrom the perspectives of the user's eyes. For example, the system maycast one or more rays 620 into the 3D space from a viewpoint thatcorresponds to each eye of the user. In this manner, the rendered images615 that are displayed to the user would be computed from theperspective of the user's eyes, rather than from the perspective of theexternal-facing cameras 105A-B.

In particular embodiments the computing system may display thepassthrough images on a device display associated with a user, forexample an HMD 104 display. FIG. 7 illustrates one or more passthroughimages displayed on a device display associated with a user. Inparticular embodiments a first output image (e.g., a left eye image) maybe displayed on a first display (e.g., a left eye display) of the deviceconfigured to be viewed by the first eye (e.g., the left eye) of theuser, and a second output image (e.g., a right eye image) may bedisplayed on a second display (e.g., a right eye display) of the deviceconfigured to be viewed by the second eye (e.g., the right eye) of theuser. In particular embodiments the computing system may displaypassthrough images outside the virtual surface. For example, if thevirtual surface corresponds to a table in the real environment, thecomputing system may display the passthrough images on the virtualsurface, as well as passthrough images for the surrounding walls, floor,etc. Passthrough images outside the virtual surface may be rendered anddisplayed according to the methods described in U.S. application Ser.No. 16/746,128, filed Jul. 24, 2020, entitled “Systems, Methods, andMedia for Generating Visualization of Physical Environment in ArtificialReality,” hereby incorporated by reference in its entirety.

In particular embodiments the display of the passthrough images may bebased on a location or orientation of the HMD 104 or user wearing theHMD 104. FIGS. 8A-8C illustrate selectively displaying passthroughimages based on a location or orientation of the HMD 104. The computingsystem may determine a location or orientation of the HMD 104, user 102,or cameras 105A and 105B and, based on the distance of the HMD 104, user102, or cameras 105A and 105B from the virtual surface 505, determinewhether to display the passthrough images on a device display associatedwith the user.

As depicted in FIG. 8A, in particular embodiments the passthrough imagesmay be displayed based on a horizontal distance of the HMD 104, user102, or cameras 105A and 105B from the virtual surface 505, for examplea minimum horizontal threshold distance. For example, if virtual surface505 represents a table in the real environment, user 102 may only beinterested in viewing the passthrough images of the table when they arewithin a certain horizontal proximity from the table (e.g., when theuser moves away from their work station). In these embodiments thecomputing system may determine a horizontal distance of the HMD 104,user 102, or cameras 105A and 105B from the virtual surface 505, basedon for example, sensor data or image data received by the computingsystem, and selectively display the one or more passthrough images basedon this horizontal distance from virtual surface 505. Although FIG. 8Adepicts only displaying passthrough images when the user 102 exceeds aminimum horizontal threshold distance from virtual surface 505, inparticular embodiments the computing system may only display passthroughimages when the user 102 is within a minimum horizontal thresholddistance from virtual surface 505.

As depicted in FIG. 8B, in particular embodiments the passthrough imagesmay be displayed based on a vertical distance of the HMD 104, user 102,or cameras 105A and 105B from the virtual surface 505, for example aminimum vertical threshold distance. For example, if virtual surface 505represents a table in the real environment, user 102 may only beinterested in viewing the passthrough images of the table when theyexceed a certain vertical proximity from the table (e.g., when the userstands up from sitting at their workstation). In these embodiments thecomputing system may determine a vertical distance of the HMD 104, user102, or cameras 105A and 105B from the virtual surface 505, based on forexample, sensor data or image data received by the computing system, andselectively display the one or more passthrough images based on thisvertical distance from virtual surface 505. Although FIG. 8B depictsonly displaying passthrough images when the user 102 exceeds a minimumvertical threshold distance from virtual surface 505, in particularembodiments the computing system may only display passthrough imageswhen the user 102 is within a minimum vertical threshold distance fromvirtual surface 505.

As depicted in FIG. 8C, in particular embodiments the passthrough imagesmay be displayed based on an orientation of the HMD 104, user 102, orcameras 105A and 105B relative to the virtual surface 505, for example aminimum threshold orientation. For example, if virtual surface 505represents a table in the real environment, user 102 may only beinterested in viewing the passthrough images of the table when they arelooking downwards towards the table, or when the table is within thefield of view of the user (e.g., when the user looks down at an objecton the table). As another example, when the user tilts his head down tolook at his own body (e.g., to reach into his pocket), the portion ofhis field-of-view that intersects a defined volume around his body woulddisplay the corresponding passthrough images based on the current viewor field of view of the user. In these embodiments the computing systemmay determine an orientation of the HMD 104, user 102, or cameras 105Aand 105B relative to the virtual surface 505 (e.g., whether the user islooking at the virtual surface, whether the camera field of viewincludes the virtual surface or real object, etc.), based on forexample, sensor data or image data received by the computing system, andselectively display the one or more passthrough images based on thisorientation of the HMD 104, user 102, or cameras 105A and 105B relativeto the virtual surface 505. Although FIG. 8C depicts only displayingpassthrough images when the orientation of the view of user 102 iswithin a minimum threshold orientation relative to the virtual surface505, in particular embodiments the computing system may only displaypassthrough images when the orientation of the view of user 102 exceedsthe minimum threshold orientation relative to the virtual surface 505.

In particular embodiments, the computing system may apply one or morevisual effects to enhance the display of the one or more passthroughimages to the user. For example, the computing system may utilize themethods described herein to determine one or more regions of the imagethat correspond to the virtual surface, and only display the regions ofthe image to the user that correspond to the virtual surface (e.g., ifthe virtual surface represents a table in the real environment, thecomputing system may omit from display the regions of the image thatcorrespond to, for example, the floor immediately adjacent to thetable). As another example, in particular embodiments the computingsystem may use shading or other visual techniques to create a gradualgradient between the passthrough images and the virtual environment. Asyet another example, in particular embodiments the display of thepassthrough images may gradually fade in or fade out based on theproximity of the user, HMD 104, or cameras 105A and 105B from thevirtual surface as illustrated in FIGS. 8A-8C and outlined above (e.g.,rather than abruptly display the passthrough images when the userexceeds the minimum horizontal threshold distance, the computing systemmay gradually fade the passthrough images in or out as the userapproaches the minimum horizontal threshold distance).

FIG. 9 illustrates an example method 900 for displaying stabilizedimages of a real environment in artificial reality. The method may beginat step 910, where a computing system tracks motions performed by a handof a user. The one or more motions may be further associated with aninteraction with one or more controllers 106, for example, movementswith the controllers or input received through one or more buttons ormechanical input mechanisms.

At step 920, the computing system determines, based on the trackedmotions, one or more anchor locations in a three-dimensional space. Ananchor location may represent a location in the three-dimensional spacethat remains at a fixed (i.e., “anchored”) position and orientation overtime. One or more anchor locations may comprise one or more coordinates,a dimension (e.g., a length), an area, or a volume. In particularembodiments the one or more anchor locations correspond to a location ofone or more objects in the real environment (e.g., an anchor locationmay correspond to the corner of a desk, a length of a wall, a maskingcanvas area, etc.).

At step 930, the computing system generates, based on the one or moreanchor locations, a virtual surface anchored in the three-dimensionalspace. In particular embodiments the virtual surface may remain at afixed (i.e., “anchored”) position and orientation over time. This fixedposition and orientation may correspond to the position and orientationof the one or more anchor locations, or physical objects in the realenvironment. The generated virtual surface, which remains fixed in thethree-dimensional space by the computing system, allows for temporalstability when projecting the passthrough images, as the definedlocation and corresponding depth of the 3D surface relative to the userand HMD 104 need not be constantly estimated and updated.

At step 940, the computing system captures an image of a realenvironment using a camera worn by the user. The camera may beassociated with a device worn by the user (e.g., an HMD 104) that blocksthe user from seeing the environment directly. The images may be stereoimage pairs captured simultaneously by two cameras with a shared fieldof view.

At step 950, the computing system determines a pose of the camera whenthe image is captured. The camera pose may be determined by utilizingany of the sensor data or image data received by the computing system.In particular embodiments the camera pose may be determined based on aknown spatial relationship between the pose of the camera and the poseof one or more components of the artificial reality system, for examplethe HMD 104.

At step 960, the computing system determines a region in the image that,as viewed from the pose of the camera, corresponds to the virtualsurface. In particular embodiments this determination may be based on,for example, the known spatial relationships between, for example, thepose of the one or more cameras on the HMD 104, the pose of the user orHMD 104, and the pose of the one or more anchor locations or virtualsurface. As another example, in particular embodiments thisdetermination can be based on one or more computer vision techniques(e.g., object recognition).

At step 970, the computing system determines a first viewpoint of afirst eye of the user (e.g., the right eye). In embodiments where theHMD 104 has one display per eye, the system may further determine asecond viewpoint of a second eye of the user (e.g., the left eye). Atstep 980, the computing system renders a first output image based on thefirst viewpoint relative to the virtual surface and the image regioncorresponding to the virtual surface. If a second output image isdesired for the user's other eye, the system may further render thesecond output image based on the second viewpoint relative to thevirtual surface and the image region corresponding to the virtualsurface.

At step 990, the computing system displays the first output image on afirst display of the device and/or the second output image on a seconddisplay of the device. The first display is configured to be viewed bythe first eye of the user and the second display is configured to beviewed by the second eye of the user.

Particular embodiments may repeat one or more steps of the method ofFIG. 9, where appropriate. Although this disclosure describes andillustrates particular steps of the method of FIG. 9 as occurring in aparticular order, this disclosure contemplates any suitable steps of themethod of FIG. 9 occurring in any suitable order. Moreover, althoughthis disclosure describes and illustrates an example method fordisplaying stabilized images of a real environment in artificial realityincluding the particular steps of the method of FIG. 9, this disclosurecontemplates any suitable method for displaying stabilized images of areal environment in artificial reality including any suitable steps,which may include all, some, or none of the steps of the method of FIG.9, where appropriate. Furthermore, although this disclosure describesand illustrates particular components, devices, or systems carrying outparticular steps of the method of FIG. 9, this disclosure contemplatesany suitable combination of any suitable components, devices, or systemscarrying out any suitable steps of the method of FIG. 9.

FIG. 10 illustrates an example network environment 1000 associated witha social-networking system. Network environment 1000 includes a clientsystem 1030, a social-networking system 1060, and a third-party system1070 connected to each other by a network 1010. Although FIG. 10illustrates a particular arrangement of client system 1030,social-networking system 1060, third-party system 1070, and network1010, this disclosure contemplates any suitable arrangement of clientsystem 1030, social-networking system 1060, third-party system 1070, andnetwork 1010. As an example and not by way of limitation, two or more ofclient system 1030, social-networking system 1060, and third-partysystem 1070 may be connected to each other directly, bypassing network1010. As another example, two or more of client system 1030,social-networking system 1060, and third-party system 1070 may bephysically or logically co-located with each other in whole or in part.Moreover, although FIG. 10 illustrates a particular number of clientsystems 1030, social-networking systems 1060, third-party systems 1070,and networks 1010, this disclosure contemplates any suitable number ofclient systems 1030, social-networking systems 1060, third-party systems1070, and networks 1010. As an example and not by way of limitation,network environment 1000 may include multiple client system 1030,social-networking systems 1060, third-party systems 1070, and networks1010.

This disclosure contemplates any suitable network 1010. As an exampleand not by way of limitation, one or more portions of network 1010 mayinclude an ad hoc network, an intranet, an extranet, a virtual privatenetwork (VPN), a local area network (LAN), a wireless LAN (WLAN), a widearea network (WAN), a wireless WAN (WWAN), a metropolitan area network(MAN), a portion of the Internet, a portion of the Public SwitchedTelephone Network (PSTN), a cellular telephone network, or a combinationof two or more of these. Network 1010 may include one or more networks1010.

Links 1050 may connect client system 1030, social-networking system1060, and third-party system 1070 to communication network 1010 or toeach other. This disclosure contemplates any suitable links 1050. Inparticular embodiments, one or more links 1050 include one or morewireline (such as for example Digital Subscriber Line (DSL) or Data OverCable Service Interface Specification (DOCSIS)), wireless (such as forexample Wi-Fi or Worldwide Interoperability for Microwave Access(WiMAX)), or optical (such as for example Synchronous Optical Network(SONET) or Synchronous Digital Hierarchy (SDH)) links. In particularembodiments, one or more links 1050 each include an ad hoc network, anintranet, an extranet, a VPN, a LAN, a WLAN, a WAN, a WWAN, a MAN, aportion of the Internet, a portion of the PSTN, a cellulartechnology-based network, a satellite communications technology-basednetwork, another link 1050, or a combination of two or more such links1050. Links 1050 need not necessarily be the same throughout networkenvironment 1000. One or more first links 1050 may differ in one or morerespects from one or more second links 1050.

In particular embodiments, client system 1030 may be an electronicdevice including hardware, software, or embedded logic components or acombination of two or more such components and capable of carrying outthe appropriate functionalities implemented or supported by clientsystem 1030. As an example and not by way of limitation, a client system1030 may include a computer system such as a desktop computer, notebookor laptop computer, netbook, a tablet computer, e-book reader, GPSdevice, camera, personal digital assistant (PDA), handheld electronicdevice, cellular telephone, smartphone, augmented/virtual realitydevice, other suitable electronic device, or any suitable combinationthereof. This disclosure contemplates any suitable client systems 1030.A client system 1030 may enable a network user at client system 1030 toaccess network 1010. A client system 1030 may enable its user tocommunicate with other users at other client systems 1030.

In particular embodiments, client system 1030 may include a web browser1032, and may have one or more add-ons, plug-ins, or other extensions. Auser at client system 1030 may enter a Uniform Resource Locator (URL) orother address directing the web browser 1032 to a particular server(such as server 1062, or a server associated with a third-party system1070), and the web browser 1032 may generate a Hyper Text TransferProtocol (HTTP) request and communicate the HTTP request to server. Theserver may accept the HTTP request and communicate to client system 1030one or more Hyper Text Markup Language (HTML) files responsive to theHTTP request. Client system 1030 may render a webpage based on the HTMLfiles from the server for presentation to the user. This disclosurecontemplates any suitable webpage files. As an example and not by way oflimitation, webpages may render from HTML files, Extensible Hyper TextMarkup Language (XHTML) files, or Extensible Markup Language (XML)files, according to particular needs. Such pages may also executescripts, combinations of markup language and scripts, and the like.Herein, reference to a webpage encompasses one or more correspondingwebpage files (which a browser may use to render the webpage) and viceversa, where appropriate.

In particular embodiments, social-networking system 1060 may be anetwork-addressable computing system that can host an online socialnetwork. Social-networking system 1060 may generate, store, receive, andsend social-networking data, such as, for example, user-profile data,concept-profile data, social-graph information, or other suitable datarelated to the online social network. Social-networking system 1060 maybe accessed by the other components of network environment 1000 eitherdirectly or via network 1010. As an example and not by way oflimitation, client system 1030 may access social-networking system 1060using a web browser 1032, or a native application associated withsocial-networking system 1060 (e.g., a mobile social-networkingapplication, a messaging application, another suitable application, orany combination thereof) either directly or via network 1010. Inparticular embodiments, social-networking system 1060 may include one ormore servers 1062. Each server 1062 may be a unitary server or adistributed server spanning multiple computers or multiple datacenters.Servers 1062 may be of various types, such as, for example and withoutlimitation, web server, news server, mail server, message server,advertising server, file server, application server, exchange server,database server, proxy server, another server suitable for performingfunctions or processes described herein, or any combination thereof. Inparticular embodiments, each server 1062 may include hardware, software,or embedded logic components or a combination of two or more suchcomponents for carrying out the appropriate functionalities implementedor supported by server 1062. In particular embodiments,social-networking system 1060 may include one or more data stores 1064.Data stores 1064 may be used to store various types of information. Inparticular embodiments, the information stored in data stores 1064 maybe organized according to specific data structures. In particularembodiments, each data store 1064 may be a relational, columnar,correlation, or other suitable database. Although this disclosuredescribes or illustrates particular types of databases, this disclosurecontemplates any suitable types of databases. Particular embodiments mayprovide interfaces that enable a client system 1030, a social-networkingsystem 1060, or a third-party system 1070 to manage, retrieve, modify,add, or delete, the information stored in data store 1064.

In particular embodiments, social-networking system 1060 may store oneor more social graphs in one or more data stores 1064. In particularembodiments, a social graph may include multiple nodes—which may includemultiple user nodes (each corresponding to a particular user) ormultiple concept nodes (each corresponding to a particular concept)—andmultiple edges connecting the nodes. Social-networking system 1060 mayprovide users of the online social network the ability to communicateand interact with other users. In particular embodiments, users may jointhe online social network via social-networking system 1060 and then addconnections (e.g., relationships) to a number of other users ofsocial-networking system 1060 to whom they want to be connected. Herein,the term “friend” may refer to any other user of social-networkingsystem 1060 with whom a user has formed a connection, association, orrelationship via social-networking system 1060.

In particular embodiments, social-networking system 1060 may provideusers with the ability to take actions on various types of items orobjects, supported by social-networking system 1060. As an example andnot by way of limitation, the items and objects may include groups orsocial networks to which users of social-networking system 1060 maybelong, events or calendar entries in which a user might be interested,computer-based applications that a user may use, transactions that allowusers to buy or sell items via the service, interactions withadvertisements that a user may perform, or other suitable items orobjects. A user may interact with anything that is capable of beingrepresented in social-networking system 1060 or by an external system ofthird-party system 1070, which is separate from social-networking system1060 and coupled to social-networking system 1060 via a network 1010.

In particular embodiments, social-networking system 1060 may be capableof linking a variety of entities. As an example and not by way oflimitation, social-networking system 1060 may enable users to interactwith each other as well as receive content from third-party systems 1070or other entities, or to allow users to interact with these entitiesthrough an application programming interfaces (API) or othercommunication channels.

In particular embodiments, a third-party system 1070 may include one ormore types of servers, one or more data stores, one or more interfaces,including but not limited to APIs, one or more web services, one or morecontent sources, one or more networks, or any other suitable components,e.g., that servers may communicate with. A third-party system 1070 maybe operated by a different entity from an entity operatingsocial-networking system 1060. In particular embodiments, however,social-networking system 1060 and third-party systems 1070 may operatein conjunction with each other to provide social-networking services tousers of social-networking system 1060 or third-party systems 1070. Inthis sense, social-networking system 1060 may provide a platform, orbackbone, which other systems, such as third-party systems 1070, may useto provide social-networking services and functionality to users acrossthe Internet.

In particular embodiments, a third-party system 1070 may include athird-party content object provider. A third-party content objectprovider may include one or more sources of content objects, which maybe communicated to a client system 1030. As an example and not by way oflimitation, content objects may include information regarding things oractivities of interest to the user, such as, for example, movie showtimes, movie reviews, restaurant reviews, restaurant menus, productinformation and reviews, or other suitable information. As anotherexample and not by way of limitation, content objects may includeincentive content objects, such as coupons, discount tickets, giftcertificates, or other suitable incentive objects.

In particular embodiments, social-networking system 1060 also includesuser-generated content objects, which may enhance a user's interactionswith social-networking system 1060. User-generated content may includeanything a user can add, upload, send, or “post” to social-networkingsystem 1060. As an example and not by way of limitation, a usercommunicates posts to social-networking system 1060 from a client system1030. Posts may include data such as status updates or other textualdata, location information, photos, videos, links, music or othersimilar data or media. Content may also be added to social-networkingsystem 1060 by a third-party through a “communication channel,” such asa newsfeed or stream.

In particular embodiments, social-networking system 1060 may include avariety of servers, sub-systems, programs, modules, logs, and datastores. In particular embodiments, social-networking system 1060 mayinclude one or more of the following: a web server, action logger,API-request server, relevance-and-ranking engine, content-objectclassifier, notification controller, action log,third-party-content-object-exposure log, inference module,authorization/privacy server, search module, advertisement-targetingmodule, user-interface module, user-profile store, connection store,third-party content store, or location store. Social-networking system1060 may also include suitable components such as network interfaces,security mechanisms, load balancers, failover servers,management-and-network-operations consoles, other suitable components,or any suitable combination thereof. In particular embodiments,social-networking system 1060 may include one or more user-profilestores for storing user profiles. A user profile may include, forexample, biographic information, demographic information, behavioralinformation, social information, or other types of descriptiveinformation, such as work experience, educational history, hobbies orpreferences, interests, affinities, or location. Interest informationmay include interests related to one or more categories. Categories maybe general or specific. As an example and not by way of limitation, if auser “likes” an article about a brand of shoes the category may be thebrand, or the general category of “shoes” or “clothing.” A connectionstore may be used for storing connection information about users. Theconnection information may indicate users who have similar or commonwork experience, group memberships, hobbies, educational history, or arein any way related or share common attributes. The connectioninformation may also include user-defined connections between differentusers and content (both internal and external). A web server may be usedfor linking social-networking system 1060 to one or more client systems1030 or one or more third-party system 1070 via network 1010. The webserver may include a mail server or other messaging functionality forreceiving and routing messages between social-networking system 1060 andone or more client systems 1030. An API-request server may allow athird-party system 1070 to access information from social-networkingsystem 1060 by calling one or more APIs. An action logger may be used toreceive communications from a web server about a user's actions on oroff social-networking system 1060. In conjunction with the action log, athird-party-content-object log may be maintained of user exposures tothird-party-content objects. A notification controller may provideinformation regarding content objects to a client system 1030.Information may be pushed to a client system 1030 as notifications, orinformation may be pulled from client system 1030 responsive to arequest received from client system 1030. Authorization servers may beused to enforce one or more privacy settings of the users ofsocial-networking system 1060. A privacy setting of a user determineshow particular information associated with a user can be shared. Theauthorization server may allow users to opt in to or opt out of havingtheir actions logged by social-networking system 1060 or shared withother systems (e.g., third-party system 1070), such as, for example, bysetting appropriate privacy settings. Third-party-content-object storesmay be used to store content objects received from third parties, suchas a third-party system 1070. Location stores may be used for storinglocation information received from client systems 1030 associated withusers. Advertisement-pricing modules may combine social information, thecurrent time, location information, or other suitable information toprovide relevant advertisements, in the form of notifications, to auser.

FIG. 11 illustrates an example computer system 1100. In particularembodiments, one or more computer systems 1100 perform one or more stepsof one or more methods described or illustrated herein. In particularembodiments, one or more computer systems 1100 provide functionalitydescribed or illustrated herein. In particular embodiments, softwarerunning on one or more computer systems 1100 performs one or more stepsof one or more methods described or illustrated herein or providesfunctionality described or illustrated herein. Particular embodimentsinclude one or more portions of one or more computer systems 1100.Herein, reference to a computer system may encompass a computing device,and vice versa, where appropriate. Moreover, reference to a computersystem may encompass one or more computer systems, where appropriate.

This disclosure contemplates any suitable number of computer systems1100. This disclosure contemplates computer system 1100 taking anysuitable physical form. As example and not by way of limitation,computer system 1100 may be an embedded computer system, asystem-on-chip (SOC), a single-board computer system (SBC) (such as, forexample, a computer-on-module (COM) or system-on-module (SOM)), adesktop computer system, a laptop or notebook computer system, aninteractive kiosk, a mainframe, a mesh of computer systems, a mobiletelephone, a personal digital assistant (PDA), a server, a tabletcomputer system, an augmented/virtual reality device, or a combinationof two or more of these. Where appropriate, computer system 1100 mayinclude one or more computer systems 1100; be unitary or distributed;span multiple locations; span multiple machines; span multiple datacenters; or reside in a cloud, which may include one or more cloudcomponents in one or more networks. Where appropriate, one or morecomputer systems 1100 may perform without substantial spatial ortemporal limitation one or more steps of one or more methods describedor illustrated herein. As an example and not by way of limitation, oneor more computer systems 1100 may perform in real time or in batch modeone or more steps of one or more methods described or illustratedherein. One or more computer systems 1100 may perform at different timesor at different locations one or more steps of one or more methodsdescribed or illustrated herein, where appropriate.

In particular embodiments, computer system 1100 includes a processor1102, memory 1104, storage 1106, an input/output (I/O) interface 1108, acommunication interface 1110, and a bus 1112. Although this disclosuredescribes and illustrates a particular computer system having aparticular number of particular components in a particular arrangement,this disclosure contemplates any suitable computer system having anysuitable number of any suitable components in any suitable arrangement.

In particular embodiments, processor 1102 includes hardware forexecuting instructions, such as those making up a computer program. Asan example and not by way of limitation, to execute instructions,processor 1102 may retrieve (or fetch) the instructions from an internalregister, an internal cache, memory 1104, or storage 1106; decode andexecute them; and then write one or more results to an internalregister, an internal cache, memory 1104, or storage 1106. In particularembodiments, processor 1102 may include one or more internal caches fordata, instructions, or addresses. This disclosure contemplates processor1102 including any suitable number of any suitable internal caches,where appropriate. As an example and not by way of limitation, processor1102 may include one or more instruction caches, one or more datacaches, and one or more translation lookaside buffers (TLBs).Instructions in the instruction caches may be copies of instructions inmemory 1104 or storage 1106, and the instruction caches may speed upretrieval of those instructions by processor 1102. Data in the datacaches may be copies of data in memory 1104 or storage 1106 forinstructions executing at processor 1102 to operate on; the results ofprevious instructions executed at processor 1102 for access bysubsequent instructions executing at processor 1102 or for writing tomemory 1104 or storage 1106; or other suitable data. The data caches mayspeed up read or write operations by processor 1102. The TLBs may speedup virtual-address translation for processor 1102. In particularembodiments, processor 1102 may include one or more internal registersfor data, instructions, or addresses. This disclosure contemplatesprocessor 1102 including any suitable number of any suitable internalregisters, where appropriate. Where appropriate, processor 1102 mayinclude one or more arithmetic logic units (ALUs); be a multi-coreprocessor; or include one or more processors 1102. Although thisdisclosure describes and illustrates a particular processor, thisdisclosure contemplates any suitable processor.

In particular embodiments, memory 1104 includes main memory for storinginstructions for processor 1102 to execute or data for processor 1102 tooperate on. As an example and not by way of limitation, computer system1100 may load instructions from storage 1106 or another source (such as,for example, another computer system 1100) to memory 1104. Processor1102 may then load the instructions from memory 1104 to an internalregister or internal cache. To execute the instructions, processor 1102may retrieve the instructions from the internal register or internalcache and decode them. During or after execution of the instructions,processor 1102 may write one or more results (which may be intermediateor final results) to the internal register or internal cache. Processor1102 may then write one or more of those results to memory 1104. Inparticular embodiments, processor 1102 executes only instructions in oneor more internal registers or internal caches or in memory 1104 (asopposed to storage 1106 or elsewhere) and operates only on data in oneor more internal registers or internal caches or in memory 1104 (asopposed to storage 1106 or elsewhere). One or more memory buses (whichmay each include an address bus and a data bus) may couple processor1102 to memory 1104. Bus 1112 may include one or more memory buses, asdescribed below. In particular embodiments, one or more memorymanagement units (MMUs) reside between processor 1102 and memory 1104and facilitate accesses to memory 1104 requested by processor 1102. Inparticular embodiments, memory 1104 includes random access memory (RAM).This RAM may be volatile memory, where appropriate. Where appropriate,this RAM may be dynamic RAM (DRAM) or static RAM (SRAM). Moreover, whereappropriate, this RAM may be single-ported or multi-ported RAM. Thisdisclosure contemplates any suitable RAM. Memory 1104 may include one ormore memories 1104, where appropriate. Although this disclosuredescribes and illustrates particular memory, this disclosurecontemplates any suitable memory.

In particular embodiments, storage 1106 includes mass storage for dataor instructions. As an example and not by way of limitation, storage1106 may include a hard disk drive (HDD), a floppy disk drive, flashmemory, an optical disc, a magneto-optical disc, magnetic tape, or aUniversal Serial Bus (USB) drive or a combination of two or more ofthese. Storage 1106 may include removable or non-removable (or fixed)media, where appropriate. Storage 1106 may be internal or external tocomputer system 1100, where appropriate. In particular embodiments,storage 1106 is non-volatile, solid-state memory. In particularembodiments, storage 1106 includes read-only memory (ROM). Whereappropriate, this ROM may be mask-programmed ROM, programmable ROM(PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM),electrically alterable ROM (EAROM), or flash memory or a combination oftwo or more of these. This disclosure contemplates mass storage 1106taking any suitable physical form. Storage 1106 may include one or morestorage control units facilitating communication between processor 1102and storage 1106, where appropriate. Where appropriate, storage 1106 mayinclude one or more storages 1106. Although this disclosure describesand illustrates particular storage, this disclosure contemplates anysuitable storage.

In particular embodiments, I/O interface 1108 includes hardware,software, or both, providing one or more interfaces for communicationbetween computer system 1100 and one or more I/O devices. Computersystem 1100 may include one or more of these I/O devices, whereappropriate. One or more of these I/O devices may enable communicationbetween a person and computer system 1100. As an example and not by wayof limitation, an I/O device may include a keyboard, keypad, microphone,monitor, mouse, printer, scanner, speaker, still camera, stylus, tablet,touch screen, trackball, video camera, another suitable I/O device or acombination of two or more of these. An I/O device may include one ormore sensors. This disclosure contemplates any suitable I/O devices andany suitable I/O interfaces 1108 for them. Where appropriate, I/Ointerface 1108 may include one or more device or software driversenabling processor 1102 to drive one or more of these I/O devices. I/Ointerface 1108 may include one or more I/O interfaces 1108, whereappropriate. Although this disclosure describes and illustrates aparticular I/O interface, this disclosure contemplates any suitable I/Ointerface.

In particular embodiments, communication interface 1110 includeshardware, software, or both providing one or more interfaces forcommunication (such as, for example, packet-based communication) betweencomputer system 1100 and one or more other computer systems 1100 or oneor more networks. As an example and not by way of limitation,communication interface 1110 may include a network interface controller(NIC) or network adapter for communicating with an Ethernet or otherwire-based network or a wireless NIC (WNIC) or wireless adapter forcommunicating with a wireless network, such as a WI-FI network. Thisdisclosure contemplates any suitable network and any suitablecommunication interface 1110 for it. As an example and not by way oflimitation, computer system 1100 may communicate with an ad hoc network,a personal area network (PAN), a local area network (LAN), a wide areanetwork (WAN), a metropolitan area network (MAN), or one or moreportions of the Internet or a combination of two or more of these. Oneor more portions of one or more of these networks may be wired orwireless. As an example, computer system 1100 may communicate with awireless PAN (WPAN) (such as, for example, a BLUETOOTH WPAN), a WI-FInetwork, a WI-MAX network, a cellular telephone network (such as, forexample, a Global System for Mobile Communications (GSM) network), orother suitable wireless network or a combination of two or more ofthese. Computer system 1100 may include any suitable communicationinterface 1110 for any of these networks, where appropriate.Communication interface 1110 may include one or more communicationinterfaces 1110, where appropriate. Although this disclosure describesand illustrates a particular communication interface, this disclosurecontemplates any suitable communication interface.

In particular embodiments, bus 1112 includes hardware, software, or bothcoupling components of computer system 1100 to each other. As an exampleand not by way of limitation, bus 1112 may include an AcceleratedGraphics Port (AGP) or other graphics bus, an Enhanced Industry StandardArchitecture (EISA) bus, a front-side bus (FSB), a HYPERTRANSPORT (HT)interconnect, an Industry Standard Architecture (ISA) bus, an INFINIBANDinterconnect, a low-pin-count (LPC) bus, a memory bus, a Micro ChannelArchitecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, aPCI-Express (PCIe) bus, a serial advanced technology attachment (SATA)bus, a Video Electronics Standards Association local (VLB) bus, oranother suitable bus or a combination of two or more of these. Bus 1112may include one or more buses 1112, where appropriate. Although thisdisclosure describes and illustrates a particular bus, this disclosurecontemplates any suitable bus or interconnect.

Herein, a computer-readable non-transitory storage medium or media mayinclude one or more semiconductor-based or other integrated circuits(ICs) (such, as for example, field-programmable gate arrays (FPGAs) orapplication-specific ICs (ASICs)), hard disk drives (HDDs), hybrid harddrives (HHDs), optical discs, optical disc drives (ODDs),magneto-optical discs, magneto-optical drives, floppy diskettes, floppydisk drives (FDDs), magnetic tapes, solid-state drives (SSDs),RAM-drives, SECURE DIGITAL cards or drives, any other suitablecomputer-readable non-transitory storage media, or any suitablecombination of two or more of these, where appropriate. Acomputer-readable non-transitory storage medium may be volatile,non-volatile, or a combination of volatile and non-volatile, whereappropriate.

Herein, “or” is inclusive and not exclusive, unless expressly indicatedotherwise or indicated otherwise by context. Therefore, herein, “A or B”means “A, B, or both,” unless expressly indicated otherwise or indicatedotherwise by context. Moreover, “and” is both joint and several, unlessexpressly indicated otherwise or indicated otherwise by context.Therefore, herein, “A and B” means “A and B, jointly or severally,”unless expressly indicated otherwise or indicated otherwise by context.

The scope of this disclosure encompasses all changes, substitutions,variations, alterations, and modifications to the example embodimentsdescribed or illustrated herein that a person having ordinary skill inthe art would comprehend. The scope of this disclosure is not limited tothe example embodiments described or illustrated herein. Moreover,although this disclosure describes and illustrates respectiveembodiments herein as including particular components, elements,feature, functions, operations, or steps, any of these embodiments mayinclude any combination or permutation of any of the components,elements, features, functions, operations, or steps described orillustrated anywhere herein that a person having ordinary skill in theart would comprehend. Furthermore, reference in the appended claims toan apparatus or system or a component of an apparatus or system beingadapted to, arranged to, capable of, configured to, enabled to, operableto, or operative to perform a particular function encompasses thatapparatus, system, component, whether or not it or that particularfunction is activated, turned on, or unlocked, as long as thatapparatus, system, or component is so adapted, arranged, capable,configured, enabled, operable, or operative. Additionally, although thisdisclosure describes or illustrates particular embodiments as providingparticular advantages, particular embodiments may provide none, some, orall of these advantages.

What is claimed is:
 1. A method comprising, by a computing device:displaying a first image of a real environment to a user captured usinga camera worn by the user; tracking motions performed by a hand of theuser in response to the displayed first image; determining, based on thetracked motions, one or more anchor locations in a three-dimensionalvirtual reality space; generating, based on the one or more anchorlocations, a virtual surface fixed in the three-dimensional virtualreality space; capturing a second image of the real environment usingthe camera worn by the user; determining a pose of the camera when thesecond image is captured; determining a region in the second image that,as viewed from the pose of the camera, corresponds to the virtualsurface; determining a first viewpoint of a first eye of the user;rendering a first output image based on (1) the first viewpoint relativeto the virtual surface and (2) the image region of the second imagecorresponding to the virtual surface; and displaying the first outputimage on a first display of the computing device, the first displaybeing configured to be viewed by the first eye of the user.
 2. Themethod of claim 1, wherein the one or more anchor locations correspondto a location of one or more objects in the real environment.
 3. Themethod of claim 1, wherein the tracking motions comprise designating afirst coordinate in the three-dimensional virtual reality space, whereinthe one or more anchor locations are based on the first coordinate. 4.The method of claim 1, wherein the camera worn by the user is associatedwith a head-mounted device worn by the user that blocks the user fromseeing the real environment directly.
 5. The method of claim 1, furthercomprising determining a horizontal distance of the user from thevirtual surface; wherein displaying the first output image is based onthe horizontal distance of the user from the virtual surface exceeding aminimum threshold distance.
 6. The method of claim 1, further comprisingdetermining a vertical distance of the user from the virtual surface;wherein displaying the first output image is based on the verticaldistance of the user from the virtual surface exceeding a minimumthreshold distance.
 7. The method of claim 1, wherein the computingdevice is an artificial reality device, further comprising determiningan orientation of the artificial reality device relative to the virtualsurface; wherein displaying the first output image is based on theorientation of the artificial reality device.
 8. The method of claim 1,further comprising: determining a second viewpoint of a second eye ofthe user; rendering a second output image based on (1) the secondviewpoint relative to the virtual surface and (2) the image regioncorresponding to the virtual surface; and displaying the second outputimage on a second display of the device, the second display beingconfigured to be viewed by the second eye of the user.
 9. One or morecomputer-readable non-transitory storage media embodying software thatis operable when executed to: display a first image of a realenvironment to a user captured using a camera worn by the user; trackmotions performed by a hand of the user in response to the displayedfirst image; determine, based on the tracked motions, one or more anchorlocations in a three-dimensional virtual reality space; generate, basedon the one or more anchor locations, a virtual surface fixed in thethree-dimensional virtual reality space; capture a second image of thereal environment using the camera worn by the user; determine a pose ofthe camera when the second image is captured; determine a region in thesecond image that, as viewed from the pose of the camera, corresponds tothe virtual surface; determine a first viewpoint of a first eye of theuser; render a first output image based on (1) the first viewpointrelative to the virtual surface and (2) the image region of the secondimage corresponding to the virtual surface; and display the first outputimage on a first display of the device, the first display beingconfigured to be viewed by the first eye of the user.
 10. The media ofclaim 9, wherein the one or more anchor locations correspond to alocation of one or more objects in the real environment.
 11. The mediaof claim 9, wherein the tracking motions comprise designating a firstcoordinate in the three-dimensional virtual reality space, wherein theone or more anchor locations are based on the first coordinate.
 12. Themedia of claim 9, wherein the computing device is a head-mounted devicethat blocks the user from seeing the real environment directly.
 13. Themedia of claim 9, wherein the software is further operable when executedto determine a horizontal distance of the user from the virtual surface;wherein displaying the first output image is based on the horizontaldistance of the user from the virtual surface.
 14. The media of claim 9,wherein the software is further operable when executed to determine avertical distance of the user from the virtual surface; whereindisplaying the first output image is based on the vertical distance ofthe user from the virtual surface.
 15. The media of claim 9, wherein thedevice is an artificial reality device, wherein the software is furtheroperable when executed to determine an orientation of the artificialreality device relative to the virtual surface; wherein displaying thefirst output image is based on the orientation of the artificial realitydevice.
 16. A system comprising: one or more processors; and one or morecomputer-readable non-transitory storage media coupled to one or more ofthe processors and comprising instructions operable when executed by oneor more of the processors to cause the system to: display a first imageof a real environment to a user captured using a camera worn by theuser; track motions performed by a hand of the user in response to thedisplayed first image; determine, based on the tracked motions, one ormore anchor locations in a three-dimensional virtual reality space;generate, based on the one or more anchor locations, a virtual surfacefixed in the three-dimensional virtual reality space; capture a secondimage of the real environment using the camera worn by the user;determine a pose of the camera when the second image is captured;determine a region in the second image that, as viewed from the pose ofthe camera, corresponds to the virtual surface; determine a firstviewpoint of a first eye of the user; render a first output image basedon (1) the first viewpoint relative to the virtual surface and (2) theimage region of the second image corresponding to the virtual surface;and display the first output image on a first display of the device, thefirst display being configured to be viewed by the first eye of theuser.
 17. The system of claim 16, wherein the one or more anchorlocations correspond to a location of one or more objects in the realenvironment.
 18. The system of claim 16, wherein the tracking motionscomprise designating a first coordinate in the three-dimensional virtualreality space, wherein the one or more anchor locations are based on thefirst coordinate.
 19. The system of claim 16, wherein the computingdevice is a head-mounted device that blocks the user from seeing thereal environment directly.
 20. The system of claim 16, wherein theinstructions further cause the system to determine a horizontal distanceof the user from the virtual surface; wherein the first output image isdisplayed based on the horizontal distance of the user from the virtualsurface exceeding a minimum threshold distance.